Universal terminal bar structure with ground contacting feature integrated into a body structure with versatile RFI suppression for electric motors

Abstract

A method of providing RFI suppression in a DC motor provides a universal terminal bar structure 70 including a positive terminal bar 72 and a negative terminal bar 76 , a first choke 80 electrically connected with the positive terminal bar, a second choke 82 electrically connected with the negative terminal bar, a first ground connection 86 constructed and arranged to electrically connect the positive terminal bar to ground, a first breakable section A between the first ground connection and the positive terminal bar, a second ground connection 88 constructed and arranged to electrically connect the negative terminal bar to ground, and a second breakable section B between the second ground connection and the negative terminal bar. Capacitor structure 90 is attached to the terminal bar structure, and the first breakable section is selectively broken, alone or in combination with the second breakable section to provide versatile RFI suppression.

1. A terminal bar structure for a permanent magnet DC motor, the structure comprising:
 a body structure, 
 a positive terminal bar and a negative terminal bar, each being carried by the body structure, 
 a first ground connection constructed and arranged to electrically connect the positive terminal bar to ground, 
 a first breakable section between the first ground connection and the positive terminal bar constructed and arranged such that when the first breakable section is broken, the connection between ground and the positive terminal bar is terminated, 
 a second ground connection constructed and arranged to electrically connect the negative terminal bar to ground, 
 a second breakable section between the second ground connection and the negative terminal bar constructed and arranged such that when the second breakable section is broken, the connection between ground and the negative terminal bar is terminated, and 
 capacitor structure attached to the terminal bar structure, 
 whereby placement of the capacitor structure and selectively breaking the first breakable section, alone or in combination with the second breakable section, provides selective radio frequency interference (RFI) suppression for the motor. 
 
     
     
       2. The structure of  claim 1 , wherein the body structure is a grommet and at least portions of the terminal bars are insert molded in the grommet. 
     
     
       3. The structure of  claim 1 , further comprising at least one first choke electrically connected with the positive terminal bar, and at least one second choke electrically connected with the negative terminal bar. 
     
     
       4. The structure of  claim 1 , wherein the body structure is a connector body and at least portions of the terminal bars are insert molded in the connector body. 
     
     
       5. The structure of  claim 3 , wherein the positive terminal bar includes a generally Y-shaped portion defining two legs that are joined to a common member, one leg defining a terminal bar connection for a certain speed operation of the motor and the other leg defining a terminal bar connection for operation of the motor at a speed less than the certain speed. 
     
     
       6. The structure of  claim 5 , wherein the at least one positive choke is connected to the common member of the positive terminal bar. 
     
     
       7. The structure of  claim 1 , in combination with the motor, the motor having an end cap and a motor case, wherein the first and second ground connections are compressed between the end cap and the motor case such that under compression, the ground connections cut into the motor case to create ground contact. 
     
     
       8. The structure of  claim 1 , wherein the capacitor structure includes a capacitor electrically connected between the positive terminal bar and the negative terminal bar, and wherein only the first breakable section is broken. 
     
     
       9. The structure of  claim 1 , wherein the capacitor structure includes a capacitor electrically connected between the first ground connection and the positive terminal bar and another capacitor electrically connected between the positive terminal bar and the negative terminal bar, and wherein the only first breakable section is broken. 
     
     
       10. The structure of  claim 1 , wherein the capacitor structure includes a capacitor electrically connected between the first ground connection and the positive terminal bar and another capacitor electrically connected between the second ground connection and the negative terminal bar, and wherein both the first breakable section and the second breakable section are broken.